1. Field of the Invention
The invention is related to a charge control agent and the toner containing such charge control agent.
2. Description of the Related Art
Charge control agent, mainly constituted by metal complexes, have been extensively used in various areas, i.e., in the toner used in forming developer for developing an image in electrophotographic technology, in which the charge control agent is used as a component material of such toners (e.g., please refer to patent documents: Public Notice 63-61347, Public Notice 2-16916, Public Notice 2002-53539, Public Notice 2531957, Public Notice 7-97530, Public Notice 2005-121776).
The metal complexes normally used as the charge control agent in toners include generally known azo-metal complexes and salicylate-metal complexes.
One side, in an image-forming process by an image-forming apparatus using electrophotographic technology, it is necessary to heat the toner image recorded on a transfer material to fix the image. In recent years, low-temperature image fixing has been used to save energy.
However, in the chemical structure of azo-metal complexes and salicylate-metal complexes, the metal ion often tends to detach from the structure. As a result, in the toners using an azo-metal complexes or a salicylate-metal complexes as the charge control agent, the detached metal ion may bridge with the resin structure, which is another ingredient of the toners. This will cause the softening-point temperature of the toners to increase. Thus, high-quality image in low-temperature fixing cannot be obtained. In addition, the image quality will be greatly affected by humidity variations in the fixing environment. These are existing problems.
Thus, metal-free chemicals, such as calixarene compounds, are used as a charge control agent for toners. Comparing with the toners using metal-complexes as charge control agent, the charge characteristics of the toners using metal-free chemicals as charge control agent are inadequate, and the charges on the toner particles are not uniform. As a result, dusting and fogging of the toner occurs because the toners particles are not sufficiently charged.